Hello Morkos,

Your apparent yield is indeed not normal.

Theoretical maximum yield for a 1 liter E. coli culture (109 cells /ml) if protein of interest is:

• 0.1% of total protein: 150 µg/liter
• 2.0% of total protein: 3 mg/liter
• 50.0% of total protein: 75 mg/liter

Thank you so much for your helpful reply, I appreciate

Biomass yield for 1 L of LB should be approx. 2 g of wet cell paste so yes, 1 g of protein does not add up.

 1 g is not a normal value. How have you measure this value? Have you measure at 280 nm or some colorimetric method (BCA, Bradford...)?